Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift
Investigation of preferred structures of planetary wave dynamics is addressed using multivariate Gaussian mixture models. The number of components in the mixture is obtained using order statistics of the mixing proportions, hence avoiding previous difficulties related to sample sizes and independenc...
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ftunivreading:oai:centaur.reading.ac.uk:1999 2023-09-05T13:21:41+02:00 Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift Hannachi, Abdelwaheb 2007-10 https://centaur.reading.ac.uk/1999/ unknown American Meteorological Society Hannachi, Abdelwaheb (2007) Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift. Journal of the Atmospheric Sciences, 64 (10). pp. 3521-3541. ISSN 1520-0469 doi: https://doi.org/10.1175/JAS4045.1 <https://doi.org/10.1175/JAS4045.1> 551 Geology hydrology meteorology 550 Earth sciences Article PeerReviewed 2007 ftunivreading https://doi.org/10.1175/JAS4045.1 2023-08-14T17:27:18Z Investigation of preferred structures of planetary wave dynamics is addressed using multivariate Gaussian mixture models. The number of components in the mixture is obtained using order statistics of the mixing proportions, hence avoiding previous difficulties related to sample sizes and independence issues. The method is first applied to a few low-order stochastic dynamical systems and data from a general circulation model. The method is next applied to winter daily 500-hPa heights from 1949 to 2003 over the Northern Hemisphere. A spatial clustering algorithm is first applied to the leading two principal components (PCs) and shows significant clustering. The clustering is particularly robust for the first half of the record and less for the second half. The mixture model is then used to identify the clusters. Two highly significant extratropical planetary-scale preferred structures are obtained within the first two to four EOF state space. The first pattern shows a Pacific-North American (PNA) pattern and a negative North Atlantic Oscillation (NAO), and the second pattern is nearly opposite to the first one. It is also observed that some subspaces show multivariate Gaussianity, compatible with linearity, whereas others show multivariate non-Gaussianity. The same analysis is also applied to two subperiods, before and after 1978, and shows a similar regime behavior, with a slight stronger support for the first subperiod. In addition a significant regime shift is also observed between the two periods as well as a change in the shape of the distribution. The patterns associated with the regime shifts reflect essentially a PNA pattern and an NAO pattern consistent with the observed global warming effect on climate and the observed shift in sea surface temperature around the mid-1970s. Article in Journal/Newspaper North Atlantic North Atlantic oscillation CentAUR: Central Archive at the University of Reading Pacific Journal of the Atmospheric Sciences 64 10 3521 3541 |
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CentAUR: Central Archive at the University of Reading |
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551 Geology hydrology meteorology 550 Earth sciences |
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551 Geology hydrology meteorology 550 Earth sciences Hannachi, Abdelwaheb Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
topic_facet |
551 Geology hydrology meteorology 550 Earth sciences |
description |
Investigation of preferred structures of planetary wave dynamics is addressed using multivariate Gaussian mixture models. The number of components in the mixture is obtained using order statistics of the mixing proportions, hence avoiding previous difficulties related to sample sizes and independence issues. The method is first applied to a few low-order stochastic dynamical systems and data from a general circulation model. The method is next applied to winter daily 500-hPa heights from 1949 to 2003 over the Northern Hemisphere. A spatial clustering algorithm is first applied to the leading two principal components (PCs) and shows significant clustering. The clustering is particularly robust for the first half of the record and less for the second half. The mixture model is then used to identify the clusters. Two highly significant extratropical planetary-scale preferred structures are obtained within the first two to four EOF state space. The first pattern shows a Pacific-North American (PNA) pattern and a negative North Atlantic Oscillation (NAO), and the second pattern is nearly opposite to the first one. It is also observed that some subspaces show multivariate Gaussianity, compatible with linearity, whereas others show multivariate non-Gaussianity. The same analysis is also applied to two subperiods, before and after 1978, and shows a similar regime behavior, with a slight stronger support for the first subperiod. In addition a significant regime shift is also observed between the two periods as well as a change in the shape of the distribution. The patterns associated with the regime shifts reflect essentially a PNA pattern and an NAO pattern consistent with the observed global warming effect on climate and the observed shift in sea surface temperature around the mid-1970s. |
format |
Article in Journal/Newspaper |
author |
Hannachi, Abdelwaheb |
author_facet |
Hannachi, Abdelwaheb |
author_sort |
Hannachi, Abdelwaheb |
title |
Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
title_short |
Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
title_full |
Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
title_fullStr |
Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
title_full_unstemmed |
Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift |
title_sort |
tropospheric planetary wave dynamics and mixture modeling: two preferred regimes and a regime shift |
publisher |
American Meteorological Society |
publishDate |
2007 |
url |
https://centaur.reading.ac.uk/1999/ |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
Hannachi, Abdelwaheb (2007) Tropospheric planetary wave dynamics and mixture modeling: Two preferred regimes and a regime shift. Journal of the Atmospheric Sciences, 64 (10). pp. 3521-3541. ISSN 1520-0469 doi: https://doi.org/10.1175/JAS4045.1 <https://doi.org/10.1175/JAS4045.1> |
op_doi |
https://doi.org/10.1175/JAS4045.1 |
container_title |
Journal of the Atmospheric Sciences |
container_volume |
64 |
container_issue |
10 |
container_start_page |
3521 |
op_container_end_page |
3541 |
_version_ |
1776202264330895360 |